Samuel John Welsh (September 17, 1879 – October 25, 1950) was a civil engineer, canal manager, and politician from Vinton, located west of the Calcasieu Parish seat of government in Lake Charles in far southwestern Louisiana.

A native of New Castle in Lawrence County in far western Pennsylvania, Welsh studied civil engineering and relocated to Vinton in 1902 after his marriage to the former Margaret Friggle (1881-1940)[1] of Oil City in Venango County, also in western Pennsylvania. The couple had five sons: John Edgar (1903-1980) of Lake Charles, James Herbert (1906-1977) and Robert Bruce (1910-2000), both of Baton Rouge, Samuel John, Jr. (1915-2000), of Houston, Texas, and William Max (1920-2004) of Sulphur, also in Calcasieu Parish. Welsh was a railroad surveyor and the manager of the Sabine Canal Company. An active Democrat, Welsh served on the Calcasieu Parish Police Jury from 1916 to 1920 and was a member of the Calcasieu Parish School Board from 1936 to 1950 and was the board president at the time of his death. He was also a member and past president of the Vinton Drainage Board. He was a member of the Methodist Church, Rotary International, and the Masonic lodge. For a short time prior to his death, he was a director of the West Calcasieu-Cameron Hospital.[2]

Welsh went missing on October 25, 1950; his body was found four days later in Dynamite Slough in Vinton.[3] He is interred beside his first wife at Big Woods Cemetery in rural Edgerly near Vinton.[2] His second wife, Fannie B. Campbell Welsh (1908-1964), who was twenty-nine years his junior, is interred at Forest Park Cemetery in Houston, Texas.[4] The S. J. Welsh Middle School in Lake Charles bears his name.[2]